Lightweight panel structure of the honeycomb core type

ABSTRACT

An improved lightweight panel structure of the honeycomb core type comprises two spaced plates or sheets arranged in substantially parallel or concentric relationship. The opposite, juxtaposed surfaces of the plates are each provided with a plurality of spaced rows of extended surface elements which project from their associated surfaces in alternate side by side relationship to each other. The extended surface elements are dimensioned and shaped so that substantially all of the extended surface elements are each in abutment at two spaced points to thereby provide the panel assembly with structural strength resistant to flexure of the plates toward each other under compressive loading or bending force acting against the panel.

[ June 19, 11973 LIGHTWEIGHT PANEL STRUCTURE OF THE HONEYCOMB CORE TYPEPrimary Examiner-Charles J. Myhre Assistant Examiner-Theophil W.Streule, J r. Attorney-Arthur Frederick [75] Inventor: Richard JosephHaberski, Emerson,

[57] ABSTRACT An improved lightweight panel structure of the honey- [73]Assignee: Curtis-Wright Corporation,

Wood-Ridge, NJ.

Nov. 1, 1971 22 Filed; comb core type comprises two spaced plates orsheets arranged in substantially parallel or concentric relationship.The opposite, juxtaposed surfaces of the 21 Appl. No.: 194,135

plates are each provided with a plurality of spaced rows of extendedsurface elements which project from their associated surfaces inalternate side by side relationship to each other. The extended surfaceelements are dimensioned and shaped sothat substantially all of theextended surface elements are each in abutment at two 4., V V su 7. 7 55 1 l l 7/ 9Fl9 ,2 4 .m mmP m.oo m m I ll UmF 1]] 2l8 555 [ll ReferencesCited spaced points to thereby provide the panel assembly UNITED STATESPATENTS with structural strength resistant to flexure of the platestoward each other under compressive loading or bending force actingagainst the panel.

165/166 X 165/170 X Wyatt 165/170 X 10 Claims, 4 Drawing Figures3,543,844 Jordon 3,111,747 11/1963 Johnson... 3,086,624 4/1963BACKGROUND OF THE INVENTION which is relatively easy and inexpensive tofabricate and in which internally brazed or welded connections areobviated.

SUMMARY'OF THE INVENTION The present invention contemplates a panelstructure of the honeycomb core type which comprises two sheets orplates arranged in substantially parallel or concentric relationship.The opposite, juxtaposed surfaces of the plates are each provided with aplurality of spaced rows of extended surface elements. Each of theextended surface elements are curved in a direction away from itsassociated plate surface. The rows of ex tended surface elements of oneplate surfaceare arranged to extend in alternate relationship with therows of extended surface elements of the opposite plate surface and withthe curvature of the extended surface elements of one plate surfacelying in an opposite direction to the curvature of the extended surfaceelements of the opposite plate surface. The length of the extendedsurface elements, spacing between rows of extended surface elements andthe degree of curvature of the extended surface elements are correlatedso that when the assembled panel structure is in use, substantially allthe extended surface elements are in abutment at two spaced points. Oneof the points of abutment is the distal end of a first surface elementengaging the next adjacent second surface element projecting from theopposite plate surface while the other pointof abutment of the firstsurface element is apoint on its convex surface spaced which pointengages a substantially corresponding point on a third surfaceelementproje'cting from the opposite plate. This interlockingrelationship of extended surface elements provides the panel'assemblywith structural strength to resist flexure of the plates toward eachother under compressive loadingor bending force acting against thepanel. The opposite plates or sheets are secured together at theiradjacent end portions in any suitable manner, such as by plates orsheets, spaced brackets, straps or the like, which serves to prevent theplates from movement in a direction away from eachother. While alltheperipheral end portions of the plates may be secured together, .itisnot essential since the securing of two opposite, adjacent end edgeportions of the plates will be effective to prevent relative movement ofthe plates away from each other.

It is preferred that the extended surface elements be formed by askiving process such as disclosed in the U. S. Patents to Kritzer, No.3,202,312 and No. 3,229,722. This method of forming the extended surfaceelements avoids the time consuming and relatively expensive step ofmetallically bonding such elements to the primary plate surface.

BRIEF DESCRIPTION OF DRAWINGS The invention will be more fullyunderstood from the following description when considered in connectionwith the accompanying drawings in which:

FIG. 1 is a view in perspective of a panel structure according to thisinvention with parts shown in crosssection for illustration purposesonly;

FIG. 2 is a perspective view similar to FIG. 1 of a panel structureaccording to another embodiment of this invention;

FIG. 3 is a cross-sectional view taken substantially along line 33 ofFIG. 1 and on a somewhat enlarged scale; and

FIG. 4 is an enlarged fragmentary view taken along line 4-4 of FIG. 3.

DESCRIPTION OF THE PREFERRED EMBODIMENT Now referring to the drawingand, more particularly, FIGS. 1, 3 and 4, the reference number 10generally identifies the lightweight panel structure of the honeycombcore type according to one embodiment of the present invention, whichcomprises two spaced sheets or plates 12 and 14 and a core consisting ofinterlocking extended surface elements 18 and 20 projecting fromopposite, juxtaposed surfaces of plates 12 and 14, respectively.

The extended surface elements 18 and 20 of the respective plates 12 and14 are arranged in spaced parallel rows. Each of the extended surfaceelements 18 and 20 is relatively thin in cross-section and curvedupwardly and toward an imaginary plane containing its connection or root22 with its associated plate. The rows of extended surface elements 18and 20 are arranged in alternate, juxtaposition to each other so thatthe curvature or bend of the elements 18 extend opposite to thecurvature or bend of extended surface elements 20. The degree ofcurvature of surface elements 18 and 20 is determined in relation to thespacing between plates 12 and 14 and the spacing between the rows sothat, in assembly, the rows of surface elements 18 of plate 12 can bereadily brought into alternate, juxtaposed relationship with the rows ofsurface elements 20 of plate 14 by merely moving plates 12 and 14 towardeach other. Also, the degree of curvature relative to the spacing of theplates and the rows of surface elements is such that each surfaceelement abuts another'surface element of the opposite plate at a pointbetween root 22 and its distal end and in abutment against the adjacentsurface element projecting from the opposite plate in the root area ofthe latter element.

The aforesaid points of abutment between the rows of extended surfaceelements l8 and 20 function to absorb the compressive forces tending tobend plates 12 and 14 inwardly toward each other and the forces whichmay tend to bend the assembly. Asindicated by the arrows, C, each of thesurface elements function to convert the compressive forces actingagainst plates 12 and 14 into force components parallel to the primaryplates as indicated by the arrows, B. These compressive or bendingforces are absorbed or dissipated by equal and opposite force componentsB exerted by the abutting surface elements. Thus, the panel structurehas high structural resistance to deformation forces and yet is light inweight.

While the abutment of juxtaposed rows of extended surface elements 18and 20 is essential to provide the panel structure with the desiredstructural strength and rigidity, such abutment is not essential whenthe panel is not under load. If surface elements 18 and 20 are out ofcontact at their distal ends or at the points between the distal endsand their root areas 22, such nonabutment is not objectionable,providing, under load and before appreciable flexure of the plates, thesurface elements come into abutment as herein described. Also, while thedistal ends of surface elements 18 and 20 are preferably in engagementin the area of the root portion of the surface element of the opposedplate surface when under load, the distal ends may abut the surface ofthe opposite plate without departure from the scope and spirit of thisinvention.

The panel structure includes suitable means for securing plates 12 and14 from movement in a direction away from each other. One such suitablemeans may be, as shown in FIG. 1, side plates 24 and 26 or, as shown inFIG. 2, spaced strips or straps 28 welded or otherwise suitably securedto the adjacent end edge portion of plates 12 and 14. For particularapplications 25 of panel structure 10, plates 24 and 26 need not besecured to all end edge portions of the plates; for example, in arectangular shaped panel two opposite edge portions of plates 12 and 14need only be secured together by plates 24, 26 or strips 28. The panelsin some other applications may be provided with connecting means forplates 12 and 14 in the nature of slip joints (not shown) which wouldpermit limited movement of the plates away from each other andsufficiently toward each other to bring extended surface elements intoselfsupporting abutment, as previously described.

As shown in FIG. 2, it is within the purview of the present invention toprovide a panel structure having curved or arcuate shaped plates orsheets 30 and 32 which are disposed in substantially concentricrelationship to each other. This embodiment of the invention onlydiffers from panel structure 10 shown in FIG. 1, in that plates 30 and32 are curved rather than flat as are plates 12 and 14 and are connectedtogether by straps 28 rather than by side plates 24 and 26. In all otherrespects the panel structure of FIG. 2 is the same as panel structure 10and, therefore, parts of the panel structure shown in FIG. 2 whichcorrespond to parts of panel structure 10 are designated by the samereference number.

It is preferred that extended surface elements of plates 12, 14, 30 and32 be produced by the skiving process as disclosed in the U. S. Patentsto Kritzer No. 3,202,312 and No. 3,229,722. Also, as is well known inthe art of skiving, the curvature of surface elements 18 and 20 isachieved by a deflecting plate disposed adjacent the cutter blade andmovable with the latter to impart to the material a predeterminedcurvature as the surface element is being cut from spaced parallel ribsin the plate surface.

It is now believed readily apparent that the present invention providesan improved lightweight panel structure which is relatively easy tofabricate and in which internal metallic bonding of core elements andplates is obviated. It is a lightweight panel having relatively greatstructural strength which is independent of x the quality of metallicbonds or welds.

5 ment of parts without departing from the spirit and scope of theinvention as the same will now. be understood by those skilled in theart.

What is claimed is:

l. A lightweight panel structure of the honeycomb 10 type comprising:

a. two spaced plates;

h. each of said plates having spaced rows of extended surface elementsprojecting from the opposite surfaces facing each other;

c. each extended surface element has a curvature extending in adirection away from its associated plate surface;

d. the rows of surface elements being disposed in alternate relationshipto each other with the curvature of the extended surface elements in onerow of a plate lying in a direction opposite the curvature of theextended surface elements in the next adjacent row of extended surfaceelements of the other plate;

e. the extended surface elements being dimensioned so that substantiallyall of the extended surface elements of one plate are in abutmentagainst the extended surface elements of the opposite plate at theircurved portions and at their distal end portions are in abutment againstthe opposite plate, whereby the extended surface elements coact todissipate forces tending to compress the plates together by convertingthe forces into oppositely directed force components, and

f. means interconnecting the spaced plates to prevent their separation.

2. The apparatus of claim 1 wherein said two spaced points are thedistal end portion of the extended surface element and a point spacedfrom the distal end.

3. The apparatus of claim 2 wherein the point of abutment spaced fromthe distal end is a point on the convex surfaces of the next adjacentextended surface elements.

4. The apparatus of claim 1 wherein one of said two spaced points ofabutment is the distal end of a first surface element in engagement withthe next adjacent second surface element projecting from the oppositeplate surface at the point of attachment of the latter to its associatedplate surface while the other point of abutment of the said firstsurface element is at a point on its convex surface in engagement with asubstanti. lly corresponding point on the convex surface of a thirdsurface element disposed on the side of the first surface elementopposite from the second surface element.

5. The apparatus of claim 1 wherein said extended surface elements areformed from the surface of their associated plates by skiving.

6. The apparatus of claim 1 wherein said extended surface elements ineach row are in close spaced relationship to each other.

7. The apparatus of claim 1 wherein the extended surface elements areeach relatively small in crosssectional dimension as compared with thecrosssectional dimension of the plates.

8. The panel structure of claim 1 wherein said plates are flat anddisposed in substantially parallel planes.

9. The panel structure of claim 1 wherein said plates are arcuatelyshaped and disposed in substantially concentric relationship.

10. A heat exchanger of the plate fin type for effecting indirect heattransfer between a plurality of fluids at different temperatures,comprising:

a. two spaced plates;

b. each of said plates having spaced rows of extended surface elementsprojecting from the opposite surfaces defining each of said passageways;

c. each extended surface element has a curvature extending in adirection away from its associated plate surface and back toward animaginary plane containing the point of attachment of the extendedsurface element to its associated plate;

d. the rows of surface elements extending from one plate surface beingdisposed between the rows of surface elements extending from theopposite plate surface and with the curvature of the surface elements inone row of said one plate surface lying in a direction opposite thecurvature of the surface elements in the next adjacent row projectingfrom the opposite plate surface;

e. the extended surface elements being dimensioned so that the distalend of a first surface element engages the next adjacent second surfaceelement of the opposite plate surface in the area of the point ofattachment of the latter to the opposite plate and the first surfaceelement also abuts at a point spaced from its distal end the nextadjacent third surface element projecting from the opposite platesurface at a substantially corresponding point spaced from its distalend; and

f. means interconnecting spaced plates to prevent their separation.

1. A lightweight panel structure of the honeycomb type comprising: a.two spaced plates; b. each of said plates having spaced rows of extendedsurface elements projecting from the opposite surfaces facing eachother; c. each extended surface element has a curvature extending in adirection away from its associated plate surface; d. the rows of surfAceelements being disposed in alternate relationship to each other with thecurvature of the extended surface elements in one row of a plate lyingin a direction opposite the curvature of the extended surface elementsin the next adjacent row of extended surface elements of the otherplate; e. the extended surface elements being dimensioned so thatsubstantially all of the extended surface elements of one plate are inabutment against the extended surface elements of the opposite plate attheir curved portions and at their distal end portions are in abutmentagainst the opposite plate, whereby the extended surface elements coactto dissipate forces tending to compress the plates together byconverting the forces into oppositely directed force components, and f.means interconnecting the spaced plates to prevent their separation. 2.The apparatus of claim 1 wherein said two spaced points are the distalend portion of the extended surface element and a point spaced from thedistal end.
 3. The apparatus of claim 2 wherein the point of abutmentspaced from the distal end is a point on the convex surfaces of the nextadjacent extended surface elements.
 4. The apparatus of claim 1 whereinone of said two spaced points of abutment is the distal end of a firstsurface element in engagement with the next adjacent second surfaceelement projecting from the opposite plate surface at the point ofattachment of the latter to its associated plate surface while the otherpoint of abutment of the said first surface element is at a point on itsconvex surface in engagement with a substantially corresponding point onthe convex surface of a third surface element disposed on the side ofthe first surface element opposite from the second surface element. 5.The apparatus of claim 1 wherein said extended surface elements areformed from the surface of their associated plates by skiving.
 6. Theapparatus of claim 1 wherein said extended surface elements in each roware in close spaced relationship to each other.
 7. The apparatus ofclaim 1 wherein the extended surface elements are each relatively smallin cross-sectional dimension as compared with the cross-sectionaldimension of the plates.
 8. The panel structure of claim 1 wherein saidplates are flat and disposed in substantially parallel planes.
 9. Thepanel structure of claim 1 wherein said plates are arcuately shaped anddisposed in substantially concentric relationship.
 10. A heat exchangerof the plate fin type for effecting indirect heat transfer between aplurality of fluids at different temperatures, comprising: a. two spacedplates; b. each of said plates having spaced rows of extended surfaceelements projecting from the opposite surfaces defining each of saidpassageways; c. each extended surface element has a curvature extendingin a direction away from its associated plate surface and back toward animaginary plane containing the point of attachment of the extendedsurface element to its associated plate; d. the rows of surface elementsextending from one plate surface being disposed between the rows ofsurface elements extending from the opposite plate surface and with thecurvature of the surface elements in one row of said one plate surfacelying in a direction opposite the curvature of the surface elements inthe next adjacent row projecting from the opposite plate surface; e. theextended surface elements being dimensioned so that the distal end of afirst surface element engages the next adjacent second surface elementof the opposite plate surface in the area of the point of attachment ofthe latter to the opposite plate and the first surface element alsoabuts at a point spaced from its distal end the next adjacent thirdsurface element projecting from the opposite plate surface at asubstantially corresponding point spaced from its distal end; and f.means interconnecting spaced plates to prevent their separation.